John Chrysostom
The Lord leaving Galilee, did not go up straightway to Jerusalem, but first wrought miracles, refuted the pharisees, and taught the disciples concerning perfection of life, and its reward; now when about to go up to Jerusalem, He again speaks to them of His passion.
He had indeed told it, and to many, but obscurely, as in that, Destroy this temple; (John 2:19.) and again, There shall no sign be given it but the sign of Jonas the Prophet. (Mat. 12:39.) But now He imparted it clearly to His disciples.
He forewarns them also in order that they should learn that He comes to His passion wittingly, and willingly. And at the first He had foretold only His death, but now that they are more disciplined, He brings forth yet more, as, They shall deliver him to the Gentiles.
This was added, that when they should see the sufferings, they should look for the resurrection.
For when sorrow comes at a time we are looking for it, it is found lighter than it would have been, had it taken us by surprise.
For the salvation of men entirely rests upon Christ’s death; nor is there any thing for which we are more bound to render thanks to God, than for His death. He imparted the mystery of His death to His disciples for this reason, namely, because the more precious treasure is ever committed to the more worthy vessels. Had the rest heard of the passion of Christ, the men might have been troubled because of the weakness of their faith, and the women because of the tenderness of their nature, which such matters do commonly move to tears.
That word Behold, is a word of stress, to bid them lay up in their hearts the memory of this present. He says, We go up; as much as to say, Ye see that I go of My free-will to death. “When then ye shall see Me hang upon the cross, deem not that I am no more than man; for though to be able to die is human; yet to be willing to die is more than human.